Since its invention in the early 1950's by Charles L. Schepens, M.D., the binocular indirect ophthalmoscope (BIO) has become an integral part of a routine eye exam among vision care providers. Using visible light, the first generation BIO allowed direct visualization of retinal anatomy and pathology by directing light to the fundus and a hand-held condensing lens, and using the reflected light to create a virtual (indirect) image of the fundus above the plane of the eye. The BIO has been the instrument of choice for medical and surgical management of patients with retinal disease including examination and treatment of peripheral retinal pathology, retinal detachment, vitreous hemorrhage and ocular trauma.
Binocular indirect ophthalomoscopy offers several advantages of direct ophthalmoscopy, including stereopsis and a much enlarged field of view and depth of field. In general, a binocular indirect ophthalmoscope includes a light source and two light observation paths for viewing the retina. The dual observation path allows for stereopsis (i.e., 3-D vision) of a patient's eye. In one binocular indirect ophthalmoscope, such as U.S. Pat. No. 6,350,031 entitled ELECTRO-OPTIC BINOCULAR INDIRECT OPHTHALMOSCOPE, incorporated herein by reference, the light source can include a near infrared (e.g., 810 nm) source.
The original Schepens BIO uses visible light to perform the imaging of the retina, which disadvantageously requires the pupils to be dilated, thereby interfering with an individual's ability to continue normal activities subsequent to the examination procedure. Eliminating the dilatation step can be a critical issue when dealing with children, or a patient suffering from other injuries, such as in a trauma center or on a battle field. Further, the visible light spectrum transmits short wavelengths of light to generate the image of the retina. The visible light spectrum as the illumination assembly for the BIO provides a methodology in which to examine an image of the retina, through the use of at least a pair of lenses. These lenses appropriately focus and collimate the visible light to illuminate the fundus and obtain an image of the fundus.
It is desirable to provide a device that utilizes illumination to provide a superior image of the subretinal and choroidal layers by penetrating deeper into the eye with longer wavelengths. It is further desirable to provide a procedure by which a medical treatment may be performed on a human eye while a practitioner, ophthalmologist or other individual tasked with the examination acquires an image of the retina.